A human bioequivalence study is conducted to establish that two or more products can provide the same/similar blood/plasma drug levels. The underlying assumption is that if the products provide the same plasma drug levels, then their therapeutic effects would be the same as well, thus would allow interchangeability of the products such as the generics.
Therefore, for all practical purposes, the bioequivalence assessment may be considered a typical analytical chemistry test where the assessment is based on determining plasma levels. For an appropriate and accurate analytical test, the test must follow some fundamental principles of analytical tests, such as specificity and validation (accuracy, precision, and reproducibility). A test cannot be validated if it is not specific.
In this regard, a bioequivalence test is a non-specific test as plasma drug levels include (confounded) variabilities from stomach emptying/motility and liver metabolism of the drug – independent of the product characteristics. Therefore, caution is warranted in establishing the quality of the test products based on the bio-equivalence test.
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